Friday, November 8, 2013

Review: Squeal Killer anti-feedback pedal

Let’s cut right to the conclusion:  The Squeal Killer works at least as well as the Kinder AFB+ at its core function of reducing feedback.  But there are a few important differences and caveats.  Read on…

The Squeal Killer has no adjustments at all.  In fact, it doesn’t matter which jack you use for microphone in or out.  The jacks are not even labeled.  The power supply is hard-wired to the box so you cannot run it with a common 9-volt power source, which could damage it.  Setup is a no-brainer.

I didn’t open up the pedal because doing so will void the warranty, and I’m sure the creators of the pedal want to preserve any trade secrets in the circuit. 

The SK pedal is dead quiet and does not introduce any noise into the signal that I could hear. 

For this review I used my Mission Chicago 32-20 1x12 amp in fixed bias mode.  It makes 35 watts and is very loud.  I typically play this amp on loud stages with no PA support.  I compared the performance of the SK to the Kinder AFB+ and to the amp with no anti-feedback device.  The harp mic I used was my 1959 Shure 440SL with the in-line volume control removed.  The review was done in my music room in my house.

I used a sound level meter to confirm my subjective judgments, but I relied on my ears to form my conclusions.

First, I played though the Mission amp with no pedals for a while to get a baseline level and tone.  I am always impressed with the tone and power of that amp.  With the amp on 5 (out of 12) it was barely edging toward feedback and sounding awesome.  Let’s call that the baseline level.


Next I plugged in through the SK pedal.  The first thing I noticed was that the pedal attenuates the signal.  The amp was not as loud on 5 as it had been without the pedal.  I was immediately skeptical that the SK pedal was no different than a lower gain tube in V1, which will reduce your loudness allowing you to turn up more but likely getting feedback at the same ultimate amplitude.

But as I cranked up the amp it got to the baseline level at about 7 with no feedback, and I was able to crank it to 9 before it started barely tipping in to feedback.  The amp was louder than it had been on 5 with no pedals.

Next was the Kinder AFB+ pedal.  This pedal does not attenuate the signal as the SK does.  I was able to crank the amp to 7 before hearing a little ringing, which is the conventional wisdom for the AFB+.  It is known for giving you about two extra notches on a loud amp.

On 7 with the Kinder pedal the amp was about as loud as it was on 9 with the SK pedal.  At these levels feedback was slightly better controlled by the SK pedal, and the sound was more natural.


The Kinder AFB+ is known for sometimes impacting the tone of your amp.  Many players say it adds a bit of crunch.  To my ear it is a small trebly rasp that is not really annoying but is there.  The SK pedal has none of that.  It sounded closer to the true sound of the amp,

I think the amp sounded best by itself, but it got louder sans feedback with either pedal.


It is common knowledge that replacing the input tube in your amp with a lower gain tube changes the slope of the amp gain, making it less steep and easier to manage.  The amp will not explode into sudden screaming feedback so abruptly.  The SK pedal has that effect but it goes farther:  It reduces feedback potential at the margins of higher volume.  It allows you to crank your amp more toward the “sweet spot” in the power tubes so you can get improved amp tone AND reduced feedback at higher levels.

Based on what I heard today I’d give the Squeal Killer a recommendation.  It certainly deserves to be in the conversation when discussing anti-feedback devices.  It gets extra credit for simplicity and lower price.

The Squeal Killer is available online from Rockin’ Ron’s Music 4 Less.  They offer a 20-day return policy if you are not satisfied.  I’ve dealt with Rockin’ Ron’s in the past and he has earned a reputation for excellent service and reliability.  That is part of my recommendation for this product.


-The SK pedal is advertised as allowing you to crank your amp to 9, and that is true but don’t expect your amp to be as loud as it is without the pedal.  The increased headroom you get before feedback is not as dramatic as they make it sound, but it is about the same increase you get with the Kinder pedal.

-It bears repeating:  The increased headroom you get before feedback is NOT dramatic but it is useful.  This pedal is not a magic bullet. 

-This review was done in a certain room on a certain day with a certain player and a certain amp.  Your results may vary.  Feedback is a demon that lives in the air and it is very unpredictable.


Several readers have asked about the readings on the sound meter, Let's not get hung up on the numbers. My review was about playing impressions, it was not a lab test. The sound meter was there only to confirm my subjective judgment that I had the pedals at equal loudness, given that the SK pedal attenuated the signal and made comparisons of the volume knob position meaningless without a baseline measurement. I'm sure somebody will come along and do a more scientific test of the SK pedal.


  1. Thank you for another great review Rick.
    -Jason Ricci

  2. The inventor has a picture of the inside of the box on his web page. An AT7 tube, a few resistors and caps. Hmmm.

  3. the squeal killer is a very effective tool,works great in situations when volume is a must ,like large room outdoors concerts ect,also i find out that works better in high z inputs rather than low z inputs,u will get the most out of your amp by using the high z,as well by using it through a p.a system linked with your favorite pedals,also try it through a solid state amp in conjunction with the lone Wolfe harp octave/harp attack excellent results this pedal is very usable and use friendly a must for harp players...Pedro Squella aka chili